1. Field of the Invention
The present invention relates to an instrument for ultraviolet irradiation and an ultraviolet irradiating apparatus for irradiating the skin with an ultraviolet radiation emitted from a light source to determine the minimum erythema dose or treat the skin according to dermatological procedures.
2. Description of the Related Art
For treating photosensitive diseases in accordance with dermatological practices, the minimum erythema dose (MED) to the skin of each patient needs to be calculated. The minimum erythema dose is judged as follows: A plurality of irradiated areas or spots are formed on the skin of the patient by means of irradiation with different levels of ultraviolet radiation intensity, and the state of the skin in each of the spots is visually examined by the doctor.
One conventional ultraviolet radiation applying apparatus that is used to form a plurality of spots with different ultraviolet radiation intensities is disclosed in Japanese laid-open patent publication No. 7-88113, for example. The disclosed conventional ultraviolet radiation applying apparatus has a plurality of holes through which pass ultraviolet radiation emitted from a light source device that is separate from the ultraviolet radiation applying apparatus, and an exposure unit having a shutter for successively opening and closing the holes one by one.
The conventional ultraviolet radiation applying apparatus operates as follows: While the ultraviolet radiation is being emitted from the light source device, the shutter is intermittently moved to successively open and close the holes one by one to form a succession of spots with different ultraviolet radiation intensities. The doctor is kept away from the patient who is irradiated with the ultraviolet radiation by the light source device, and remotely controls the shutter mechanism. Therefore, the doctor is prevented from being exposed to the ultraviolet radiation.
The light source device that is used in combination with the conventional ultraviolet radiation applying apparatus is generally used to treat the patient by applying ultraviolet radiation, and is installed in a dedicated irradiation chamber which is dedicated to irradiate the patient with ultraviolet radiation. To measure the minimum erythema dose that is to be administered to the patient is accomplished by having the patient remain in the chamber and holds the ultraviolet radiation applying apparatus over the region of the body that is to be irradiated with ultraviolet radiation, then a plurality of spots are formed on the body region by the ultraviolet radiation that has been applied. Therefore, the conventional ultraviolet radiation applying apparatus is disadvantageous in that the body region where the spots are formed for measuring the minimum erythema dose as well as other body regions of the patient are exposed to the ultraviolet radiation emitted from the light source device.
Measuring the minimum erythema dose with the conventional ultraviolet radiation applying apparatus, it is necessary to provide a dedicated irradiation chamber in which the ultraviolet radiation applying apparatus is installed, and a shield needs to be installed to block the ultraviolet radiation emitted from the light source device. Accordingly, the conventional ultraviolet radiation applying apparatus requires sufficient installation space for measurement.
With the conventional ultraviolet radiation applying apparatus, furthermore, when the patient is irradiated with ultraviolet radiation, the doctor is required to operate the light source device, and needs remain away from the patient who is irradiated with the ultraviolet radiation by the light source device, or needs to be protected by the shield against exposure to the ultraviolet radiation emitted from the light source device. Consequently, the process of measuring the minimum erythema dose with conventional ultraviolet radiation applying apparatus has been relatively complex to perform.